Ender 3 Fan Duct Modifications

[vtcnc]

Recently acquired a 3D Printer and have been plinking away making a few little things here and there. One weak spot in my opinion is the extruder fan and cooling fan arrangement. Here is a stock photo of the setup:

There are two 24V fans on the hot end. The axial fan on the front cools the extruder hot end. The centrifugal fan on the right cools the filament as it is extruded onto the print. Air is ducted downward and to the left of the hot end across the tip of the nozzle from the centrifugal fan.

One thing I like about this setup is that it looks simple, compact, neat and tidy. There are not a lot of wires dangling about and the hot part of the extruder is well guarded so it is safe. That's about it though - keep in mind my opinion is based on my limited experience with the machine.

The one thing I don't like about it is that it is actually not simple, and it isn't necessarily easy to work on. It is hard to see the extruder tip - the working end of the 3D printer - so you need to twist and bend downwards to watch and see what is happening. I'd prefer an easy viewing window as the machine is working. Also, the axial fan is bonded or something like glued or double-side taped to the sheet-metal guard. One of my fan blades broke off (cheap import axial fan) and so I went to remove the fan to replace it. I couldn't remove the fan from the guard. And the guard is the only way to mount the fan with this design. The more I work on this thing, the less I like it.

So, I went on the internet and started reading about this hot end and it turns out there are about 101 different hot end ducted modifications you can download and print. Being a tinkerer and having some free-time, I convinced myself that I can do better. We will see.

I order a couple of 24V centrifugal fans off eBay. These seem to have more airflow and appear to be the more popular choice for most modders on sites like Thingiverse.

I dubbed around with orienting the fans in certain directions to come up with some aesthetically pleasing design in F360. I eventually came up with the following prints:

1) This is the backplate. Extruder cooling on the left, nozzle tip cooling on the right. The hot end is installed between the two plenums. It will bolt right to the X axis carriage. You may also notice I've modeled my own plenums for the centrifugal fans.
































I couldn't get things to look streamlined. All of mods out there for ducted fans has the fans installed with their factory plenums (I hope that is the right word). The fans stick out all over the place. I want them out of the way, but where I can see that they are rotating and functioning. So, basically I'll be removing the fans from their plenums and installing them on to the back plate:



I had to model covers for each of the fans and their corresponding plenums. Here they are mid-print:



And here is some of the latching detail for the covers.


Those thin walls and latches are about .028" thick. The level of detail these machines can achieve is remarkable.

Will be working on fitting up the fans and making sure the latches securely keep the covers in place. More photos to come in a few days.

 

[MikeWi]

There are hundreds and hundreds of duct and mounting solutions out there, but I've never seen one like this! Very original I can't wait to hear how it works.

 

[vtcnc]

Got the duct modification installed and ran a test print tonight. Here are a couple of pics of the installation and a pic of it mid run. I'll upload a video at some point later.

Removed the standard fans by snipping them free from their leads:



Here is the 3d print installed in place:



Fan installation: fish the leads through each respective hole and solder. A firm dab of hot glue in the center hole of each fan location keep the fan in place. This first installation/print didn't result in perfectly centered fans in the shrouds after they were clipped into place.



Regardless, the first test print - a 1/2" knockout plug for my panel, was a success. Fans ran properly and I could see what is going on during the print.

 

[Boswell]

looks nice. Are you worried that the heat from the hot-end will soften the duct while in use?

 

[vtcnc]

looks nice. Are you worried that the heat from the hot-end will soften the duct while in use?

Not too worried. The test print was 14 minutes long. I could touch the heat sink and it was cool to the touch. Longer prints may affect the PLA. We will have to see.


Sent from my iPhone using Tapatalk

 

[Boswell]

You hot end is well insulated compared to mine. No way i could touch the outside of the Hot End during a print.

 

[vtcnc]

The hot end has a silicone boot on it. I brushed a finger against it and it was HOT. The red heatsink, on the other hands was cool to the touch.

 

[vtcnc]

UPDATE:

A couple of minor changes, but V2 is a slight improvement in the following areas:

• @Boswell was right. The backplate next to the hot end was affected. It wasn't warped or burnt, but appears to be delaminating. I'm guessing the constant thermal cycling right in that area. V2 just cut that area out to avoid exposing it to heat.
• My fancy little clasps, while durable, were a pain the keister trying to get them to clasp. I decided to see if I could get a friction fit to work.
• The filament tube is redirected off center by the plenum of the extruder fan. This was an oversight in my initial design. Move the plenum to the left.
• Hot gluing the motors to the backplate, while easy and initially effective, was not lasting. I also oversized the pilot holes to get them better centered and used double sided tape to mount the fans.

Below is an action shot of V2. You can see the hot end is entirely in the open, nothing around the block to take heat. The plenum shrouds work extremely well with a friction fit. I printed for four hours today and there were no problems with them hanging on. You can see the filament tube is now top dead center above the hot end. Another effect this eliminated was the filament tube pushing the plenum cover off.



One error I made was somehow I didn't carry over the little tail on the print cooling fan down near the hot end tip. The ventilation is excellent. Lots of air coming down that long plenum, but it is shooting down onto the plate and not across the print and tip like it should be. The print you see in the photo had a little too much cooling so far away from the tip and the corner of the printed lifted off the glass bed just a hair.

V3 is in the works:

• Holes for tie wraps to dress up the wiring and filament tube,
• Air cooling duct on print cooling fan is directed at the tip,
• Connectors for fan motors (make this solder free)

 

[tenchi13]

@vtcnc

I just had to make an account to express how impressed I am with your project.

It's so great that you have approached the problem from a new perspective.

I' ve just converted my Ender 3 to DD with a minimalistic fan duct, but I'm very interested in what you are creating here.

I hope you make good progress.
Best of luck to you.

 

[vtcnc]

@vtcnc

I just had to make an account to express how impressed I am with your project.

It's so great that you have approached the problem from a new perspective.

I' ve just converted my Ender 3 to DD with a minimalistic fan duct, but I'm very interested in what you are creating here.

I hope you make good progress.
Best of luck to you.

Thanks for the words of encouragment! A great first project post from you would be to see your direct drive on your Ender 3! Post pictures! We love pictures!